Impart energy absorbing apparatus for motor vehicles are known, for example as disclosed in U.S. Pat. Nos. 3,392,599, 3,788,148, 4,006,647 and 5,984,354. Such apparatus, which are intended for use in the steering shaft of a vehicle, comprise a shaft enclosed by an outer cylindrical sleeve in a telescopic manner, and a number of balls rotatably mounted in the gap between the shaft and the sleeve. Upon impact, the sleeve and shaft collapse relative to each other, with the balls continuously rolling therebetween to absorb the impact energy.
Although part of the impact energy will be absorbed as described, much of the impact energy will remain unabsorbed and be applied continuously to the vehicle, hence injuring the driver. Furthermore, the structures of those apparatus are complicated and not easy to install or replace.
The invention seeks to mitigate or at least alleviate such problems by providing an improved impact absorber.